Apparatus for shooting material into cupolas



A. REXROTH March 5, 1957 APPARATUS FOR SHOOTING MATERIAL INTO CUPOLAS Filed Aug. 18, 1954 ATTORNEYS APPARATUS FR SHOOTING MATERIAL INT CUPOLAS Alfred Rexroth, Eisenwerk, Lohr (Main), Germany Application August 1s, 1954, serial No. 450,738

7 Claims. (Cl. 3D2-36) ated charging device for injecting scrap metal and/orv other materials commonly used in foundry work, such as silica, calcium silicate, manganese, lime, etc. into the melting zone of a cupola or blast furnace.

Two types of injecting devices have been used heretofore. One type comprises 4a screw conveyor or a reciprocating piston for mechanically forcing or pushing the metal shavings or the like into the melting zone. This type of mechanism is subject tothe disadvantage that the moving or sliding parts develop friction, and hence are subject to considerable wear, requiring frequent replacement. Furthermore, such apparatus is inclined to develop undesirable obstruct-ions due to the mechanical pressure on the material being fed, thereby causing interruptions in the operation. This results in undesirable non-uniformity of results. Attempts have been made to press the scrap metal into briquettes before injection by this method but the results have not been satisfactory. The briquettes can be formed only under high pressure requiring heavy and expensive briquetting machinery so that any advantages realized in the injection operation, are more than offset.

A second type of charging device does away with some of the disadvantages attendant the use of mechanically moving parts, by using compressed air to force the material into the melting zone. The force imparted to the material in this way, however, is not suicient to obtain good distribution of the material in the melting zone, or to prevent the formation of obstructions in the canal leading into the cupola. Another disadvantage arises from the chilling eiect arising from blowing of cold 'air into the melting zone.

Both methods have the additional disadvantage that the melting of the injected material takesplaceina very limited space adjacent the mouth'of the lead-in canal. Slag on the furnace Wall and thedripping of slag and iron at -the inner end of -the lead-inicanal bring about disturbance of the injected charge, thus destroying the necessary evenness or uniformity of melting. For these reasons, only relatively small proportions of shavings, borings, etc. can be employed compared to the melting capacity of the cupola.

It is an object of the present invention to provide a pneumatically operated charging device which is economical of power, provides better distribution of the injected material in the melting zone and at the same time eliminates choking or slagging of the lead-in canal.

The accompanying drawing illustrates one embodiment of the present invention in side elevation, partly in section.

N represents the melting zone of the interior of a conventional cupola or blast furnace. The furnace has the usual metal shell 10 and lining 11. The device of this invention is mounted by any suitable means on the shell 10, for example, by anges 12. The cupola is equipped PatentedMar; 5, 1957 with the usual tuyeres for introducing air, and with means for introducing the various materials to be charged, including coke. A passageway 13 is provided in the lining 11 to accommodate the lead-in pipe or canal`14 which may be of suitable heat resistant metal. The pipe 14 extends only part way through the brick work lining. The opening 13 comprises the'remaining part of the canal through which material is injected into the melting zone. A check-valve C, hinged at 15, is provided in the canal 14. AValve C, which is inclined from top to bottom in the direction of the cupola may be spring loaded by suit-V able means, not shown, so that it is biased in normally closed position as shown, and rests against a seat 16. According to the embodiment shown, valve C is biased to closed position by air pressure applied through the pipe G. The air is supplied under pressure from the duct L and the pipe O. The duct L may be the manifold for supplying air to the tuyeres Vat the base of the cupola. This air may be at the pressure at which the air supplied to the tuyeres of the cupola for effecting burning of the coke to furnish the heat for melting of the cupola charge. The pressure of the air being somewhat above that in the burning zone of the cupola opposite the lead-in canal, holds the valve C in normally closed position. The cold air also tends to cool inlet sleeve 14 and to prevent ame from entering the mouth of the lead-in canal. Cold air from any source may be employed provided the pressure is greater than that in the interior of the cupola. The quantity of air passing through the lead-in canal is comparatively small so that it has negligible adverse chilling effect upon the operation of the cupola. The charging chamber B .is an extension of the lead-in pipe 14. lt is provided with a hopper A for intermittently filling the chamber B with `the shavings, borings, or other suitable scrap metal of suitable size, which is to be injected into the cupola.

Arotatable sleeve D is provided with a slot or opening 17 which, when in loadingposition, is in register with the outlet of hopper A. The sleeve D isprovided with a lever F which can be rotated around the axis of the pipe B so as to'bring the opening 17 into or out of register with the outlet of `hopper A. A slot 1S is cut part way around rthe wall'of chamber B to permit the lever arm F to `be rotated from the open position shown, to the closed position. A quick acting valve K is provided in the end of tube B remote vfrom the cupola. This in turn is connected with a supply of compressed gas such as air, entering through' pipe l. The valve K is designed for intermittent operation and may be manually or automatically controlled, as Vmay the lever F. The com-l pressed air is supplied at a substantially higher pressure than the airentering through pipe G, so 'that when itis turned on,gthe greater pressure will force the charge of scrap against valve C, and force it'open.

A magnet H is interposed between vthe flange 12 and the valve C externally of the canal 14. The poles of the magnet are attached to an electrical indicating device M. This may be a ring magnet, or two oppositely disposed magnetic devices. A magnetic eld is set up across the lead-in canal 14.

At the start of the operation, the valve C is held closed by the air pressure from the pipe G or by mechanical means such as a spring when this is used. The valve K is closed and the handle F of sleeve D is rotated to the position shown to bring the opening 17 into register with the outlet of feed hopper A. This causes the chamber B to be lled from the hopper with the turnings or other scrap metal or materials it is desired to inject. The handle F is then rotated so that the slot 17 is no longer in register with the hopper outlet and the chamber B are sealed from the hopper. Valve K is opened and the blast of compressed air striking the base of the material avancer in the chamber B forces it violently up against the valve n C. Due to the sudden. application. of force, and the momentary resistance of valve C, the materials are compacted to a certain extent to form a cylindrically shaped slug. before itv swings open tov permit. the charge, toipass.-

into the cupola. Thus the metal strikes the melting zone as a more or less compact mass rather than as more or less individual pieces as in previous practice. In effect it is shot through the leadein pipe 14 and the corre.- sponding vopening 13 in the brickwork wall, and thence into the melting zone of the cupola. Small pieces of coke, slagV or the like which might lie in the mouth of the shooting canal are demolished and larger piecesV are pushed aside by the rapidly moving slug so .that the injected material penetrates deep intothe interior of the cupola. Upon striking-the bed of material in the melting zone, the slug breaks up into lumps or pieces which penetrate deep into the glowing coke bed. As they penetrate into the coke an immediate slagging of. the individual pieces occurs, followed quickly by'melting after twoy toY tive seconds. As a consequence, the injected charge is Well distributed through the melting zone which results in even melting and a remarkable saving of coke.

Because of the good distribution and of the intermittent shooting, the material in a following shot never contacts partly melted material from a previous shot which would interrupt the continuity of the melting process.

As previously mentioned, other modifying materials commonly employed in cupola melting may be injected in the form of grains or shot, etc. with the scrap metal being charged. This furnishes a means for controlling the composition and quality ofthe melt. These include silica, calcium silicate, manganese, lime, etc. It may include coke-.sand or metal shavings or borings mixed with oil, the latter being a preservative against iron-mould.

By equipping the cupola with several of these devices distributed around the melting zone, the entire metal charge may comprise the shavings, borings and the like, to be melted. The result is a new kind of work for cupolas.

When the slug of material passes through the magnetic field set up in canal 14 by the magnet H there is achange in the strength of the field which can be detected by the indicating device M. From the change in theV magnetic eld and the duration of the change, the approximate quantity of material introduced per shot can be determined. The indicating device M may also be a counter so that the number of charges introduced can be determined. It can also be determined whether material `is being passedV through the shooting pipe. This is useful in determining whether the supply from the hop- 4 the resulting gases propel the slug of material' into the cupola in a manner similar tov shooting Vit, trpm a gun. This has the advantage that no cold air reaches the melting zone when the charge lis shot into it. Suitable propellants and means for introducing them into the chamber B will be apparent to one skilled in the art.

I claim as my invention:

l. An apparatus for injecting a material to be melted, such as metal shavings, borings and the like, into the melting zone of a cupola, blast furnace and the like, comprising a pipe forming a lead-in canal, a charging chamber, a check valve between said canal and said chamber, means biasing said valve into normally closed position; a hopper mounted on said charging chamber, valve means for intermittently opening and closing the hopper outlet whereby a charge of material to be melted can be introduced from said hopper into said charging chamber, means for intermittently supplying a propellant gas to apply sudden pressure to the end of said charge remote from said check valve, said pressure being substantially in excess of the closing forces exerted thereon, whereby said chargeis compacted and propelled into said melting zone as a slug, and means for mounting said device with said pipe extending through the wall of said cupola or blast furnace in communication with the interior thereof.

2. The apparatus of claim l wherein said propelling means comprises means for intermittently supplying com# pressed gas to said chamber.

3. The apparatus of claim 1 wherein said check valve is maintained in closed position pneumatically.

4. The apparatus of claim l wherein the check valve is maintained in closed position by air pressure exerted' on theV face remote from the charging chamber, and the propelling means comprises means for intermittently supplying gas to said chamber at a pressure greater than valve-closing air pressure.

5. The apparatus of claim 1 wherein the propelling force on said charge is supplied by an explosive material.-

6. The apparatus of claim l wherein the valving means between said valve and the mounting means, and means for detecting the extent and duration of changes in the' magnetic field due to the passage therethrough of a charge of material to be melted.

References Cited in the le of lthis patent UNITED STATES PATENTSv Lane Jan. 26, 1954 

